Scandisk and Defrag will fail on most machines today. It's a side effect of all we add to the base OS. ALL that is noted at http://support.microsoft.com/?id=222469 applies to your issue.
You'll see many answers, but this article pretty much covers it all.
For example, items in the Quicklaunch can thwart this (noted in the article) as well as a firewall.
Bob
The "Scheduled tasks" are set to run during the night,but they don't. (I got out of bed during the night to check). Neither do they run if I leave the computer in safe mode. Nor when I turn off the programs that run in the background. I should say that Norton Antivirus runs as scheduled but Scandisk and Defrag don't. We are running Windows ME. Any suggestions? Thanks.

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